Re: [OMC-Boats] Cylinder #1

From: Andy Perakes <aperakes@...>
Date: Wed, 9 Sep 2009 22:09:20 -0400

Is there any scoring on any of the cylinder walls (the look clean in the
pictures, but...)? Anything that would nick a piston would almost certainly
leave some kind of witness marks on the cylinder walls too. If it causes a
"ground out" between the piston and the valve body, it will make a big
noise, no matter how small. I'd be surprised if that alone would cause a
stall without generating obvious damage though -- maybe if it jammed up the
valve train, I suppose. Likewise, I doubt anything in the oil pan would
cause a stall without generating an obvious gut-wrenching noise and
similarly obvious damage.

Is it a regular noise that tracks with rpm or an intermittent noise?
Something that tracks rpm orders would clearly be hard-coupled to motion
whereas something rolling around in the pan would likely be random. If a
connecting rod smacked something in the pan, it could leave "ping" marks in
the oil pan that might be visible. If that's the case, I'd be worried about
one or more bent rods, but they would likely vibrate like mad before
eventually self-destructing. If it weren't for the stall, it could be skirt
or rod slap -- are you sure the stall is related to the noise and not just a
coincidence? I think its safe to say you have all of our curiosity stirred
and we'll be anxious to hear what it is!

'67 Reveler

----- Original Message -----
From: "jd" <jdood@...>
To: "Evinrude the 1960's and 70's & Johnson Boats of"
Sent: Wednesday, September 09, 2009 6:24 PM
Subject: [OMC-Boats] Cylinder #1

>I got up super close and checked out this one. No "pitting". But
> some little dings from about 4 o'clock to 8 o'clock. Right where
> gravity would hold something. Wish iPhones had macro lenses, but it
> looks like teeth marks from a cat or something. Could a cat have
> gotten in there? Sorry. Anyway, now i wondering if this is related
> and i just missed whatever came out of there when i took off the
> head. Regardless, still cant see how spmething that would cause such
> tiny nicks could mske such a big noise and cause stalling. Plus I
> thought the zero gap plug came out of the middle, not this one.
> Sheesh.
> Option 1, I put everything back together and do a test to see if noise
> still there. Possibly wont be now that whatever caused nicks on
> piston 1 is gone. Keep in mind boat ran great judt before this noise.
> Old head gaskets seem pretty good / recent. No sticking, still in
> tact. Ok to re-use?
> Opion 2
> Take out engine, inspect oil pan, etc. Probably done for season.
> Again....will undoing the front motor mounts and those back bolts
> around flywheel housing allow me to pull the engine out with a hoist?




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Received on Wednesday, 9 September 2009

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